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Inkjet printing apparatus and preliminary discharge control method of said apparatus

a control method and inkjet printing technology, applied in printing, other printing apparatus, etc., can solve the problems of discharge failure, decrease in the amount of ink that can be used in actual printing, increase in the viscosity of ink, etc., to prevent deterioration in printing quality, reduce the amount of wasted ink, and suppress the effect of throughpu

Inactive Publication Date: 2009-04-14
CANON KK
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention provides an inkjet printing apparatus and method that can prevent decreased throughput and increased waste of ink while maintaining good printing quality. This is achieved by performing a preliminary discharge under a predetermined condition to obtain information about the discharge state of the printhead, and controlling the execution condition of the preliminary discharge based on the obtained information. This allows for appropriate control of the preliminary discharge based on the discharge state of the printhead, which can vary depending on individual differences, usage environment, and so on. The detection means may include performing the preliminary discharge multiple times and changing the interval between discharges to obtain the information, or detecting the time between designation of the preliminary discharge and ink detection. The control means may set the execution condition of the preliminary discharge based on a table generated in advance or based on the information obtained during the detection step. The construction of the printing apparatus may include scanning the printhead in a direction crossing the printing medium. The invention also provides a computer program and storage medium for implementing the preliminary discharge control method.

Problems solved by technology

The first reason is that, when printing is not performed for a long time, a volatile component (solvent) of ink evaporates from the nozzle end of the printhead and ink viscosity increases, causing discharge failure.
However, if the ink discharge amount of preliminary discharge is increased, the amount of wasted ink increases and the amount of ink that can be used in actual printing decreases, resulting in an increased ink cost.
Furthermore, if the frequency of preliminary discharge is increased, the throughput decreases and the printhead life shortens due to an increased number of discharges.
Meanwhile, when a preliminary discharge is performed on a sheet of printing paper, little influence is imposed on the image quality in a case where the dots formed on the paper by preliminary discharge are microscopically small and the number of the dots is small, but unwelcome effects ensues in the image quality in a case where the ink discharge amount and the frequency of preliminary discharge are increased.

Method used

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  • Inkjet printing apparatus and preliminary discharge control method of said apparatus
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first embodiment

[0049]FIG. 8 is a perspective view showing an external appearance of an inkjet printing apparatus according to the first embodiment, whose cover is removed. The printing apparatus according to the first embodiment is a so-called serial-scan printer which forms images by scanning a printhead in the direction (main-scanning direction) crossing to the printing medium conveyance direction.

[0050]First, a brief operation at the time of printing is described. A printing medium is conveyed to a printing position by a sheet-feeding roller 6 which is driven by a sheet-feeding motor 5 through a gear. A carriage motor 3 is driven for scanning a carriage unit 2 through a carriage belt 4 in the direction crossing to the paper conveyance direction, and printing is performed for a bandwidth corresponding to the printhead's printing width. Then, the printing medium is conveyed for a predetermined distance. Alternate execution of the scanning and the printing medium conveyance realizes printing on a ...

second embodiment

[0083]Hereinafter, the second embodiment of the present invention is described. The second embodiment also provides an inkjet printing apparatus similar to the first embodiment. In the following description, the part similar to that of the first embodiment will not be described, but characteristic part of the second embodiment will mainly be described.

[0084]While the first embodiment controls the preliminary discharge interval based on the standby time that has caused discharge failure, the second embodiment controls the preliminary discharge amount based on the standby time that has caused discharge failure.

[0085]In the first embodiment, since the frequency of preliminary discharge execution changes, substantial printing speed also changes. To prevent such change, according to the second embodiment, instead of setting a preliminary discharge interval in step S105 in the flowchart in FIG. 1, the number of ink droplets (number of discharge) discharged by preliminary discharge is set ...

third embodiment

[0088]Hereinafter, the third embodiment of the present invention is described. The third embodiment also provides an inkjet printing apparatus similar to the first and second embodiments. In the following description, the part similar to that of the foregoing embodiments will not be described, but characteristic part of the third embodiment will mainly be described.

[0089]While the foregoing embodiments control (set) the preliminary discharge condition based on the standby time that has caused discharge failure, the third embodiment controls (sets) the condition of preliminary discharge on a sheet based on the standby time that has caused discharge failure.

[0090]More specifically, the printing apparatus according to the third embodiment does not execute normal preliminary discharge which is performed at a predetermined position outside the printing area, but executes preliminary discharge on a sheet, in which microscopic dots that are microscopic enough so as not to affect the appear...

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PUM

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Abstract

In an inkjet printing apparatus which performs printing on a printing medium using an inkjet printhead for discharging ink, preliminary discharge, where ink discharge irrespective of printing is performed at the time of print execution, is performed under a predetermined condition to obtain information regarding a discharge state of the printhead. Based on the obtained information, an execution condition of the preliminary discharge is controlled. By virtue of this control, an execution condition (parameter) of the preliminary discharge can appropriately be controlled in accordance with the discharge state of the printhead, in which the ink drying state and the increased viscosity state of ink vary depending on individual differences, usage environment, usage histories (durability) and so on.

Description

FIELD OF THE INVENTION[0001]The present invention relates to an inkjet printing apparatus and a preliminary discharge control method of an inkjet printing apparatus, and more particularly, to a method of controlling an execution condition of preliminary discharge, where ink discharge irrespective of printing is performed at the time of print execution, in an inkjet printing apparatus which performs printing on a printing medium using an inkjet printhead for discharging ink.BACKGROUND OF THE INVENTION[0002]As a data output apparatus of word processors, personal computers, facsimile machines and so forth, printers capable of printing desired information such as texts and images on a sheet-type printing medium, e.g., paper, film and the like, are widely utilized.[0003]Although various printing methods are available for such printers, recently an inkjet printing method has particularly attracted attention because of its capability to perform non-contact printing on a printing medium suc...

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): B41J2/165B41J2/175B41J2/01B41J2/07B41J29/393
CPCB41J2/16526
Inventor SUZUKIKANEMATSU, DAIGOROTAKEKOSHI, RIENAGAMURA, MITSUTOSHIBABA, NAOKO
Owner CANON KK